1. Field of the Invention
The present invention relates to a method for removing water from a movable roll jacket surface in a wet section of a paper-making machine, which roll jacket surface preferably belongs to a flexible roll jacket in a shoe press, said method comprising the following steps:                arranging a spray device next to the roll jacket surface,        setting up a collecting device which is provided with an opening and collects liquid,        moving said roll jacket surface past said spray device,        applying a medium onto said roll jacket surface with the aid of said spray device, and        collecting liquid in said liquid-collecting device or liquid-receiving device.        
2. Description of Related Art
In a wet section of a paper-making machine, large quantities of water have to be removed from the fiber web. This is done with, inter alia, the aid of pairs of rolls which form a nip for pressing/sucking water out of the fiber web. A certain amount of water remains behind on the roll jacket surface after the nip. In many situations it is desirable to remove at least the majority of the remaining water before that part of the roll jacket surface passes through the nip again.
It is already known, for example from U.S. Pat. Nos. 4,852,209 and 5,810,974, to set up spray devices which can clean (and/or cool) a roll jacket surface. However, this known technique does not deal with the problem of how to remove water from the roll jacket surface.
A press device in a wet section is already known from EP 771,903, where the roll jacket surface of one of the roll pairs is sprayed with water, after which a special scraping device (called a doctor blade) removes water from the roll jacket surface. DE 19860735 shows that it is also already known to arrange a scraping device/doctor blade solely for the purpose of removing water, i.e. without first spraying the roll jacket surface. Similar cleaning and dewatering devices are also already known from U.S. Pat. No. 5,520,782, DE 19841637, DE 19860735 and DE 19810800.
However, it is not always desirable to use a scraping member which is in direct contact with the roll jacket surface. In the case of a shoe press roll, where a flexible roll jacket is used, it may be particularly undesirable because the flexible roll jacket is often relatively sensitive and expensive.
There is a risk that such a scraping member may destroy the flexible roll jacket or at least accelerate its wear, in the same way that it can also cause damage on another type of roll surface.
A further disadvantage of known dewatering devices according to the above is that they have a very limited effect if the roll jacket surface from which water is to be removed is patterned, i.e. provided with grooves, for example of the type described in U.S. Pat. No. 4,559,258.